#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

void solve() {
    int n;
    cin >> n;
    multiset<int> mul, mur;
    while(n--) {
        string op; cin >> op;
        int l, r; cin >> l >> r;
        if(op == "+") {
            mul.insert(l);
            mur.insert(r);
        }else{
            mul.erase(mul.find(l));
            mur.erase(mur.find(r));
        }
        if(mul.size() && *mul.rbegin() > *mur.begin()) {
            cout << "YES" << endl;
        }else{
            cout << "NO" << endl;
        }
    }
    cout << endl;
}

int main() {
    solve();
    return 0;
}